Lifecycles control who can do what to an object at any state of its existence. The Lifecycles list in References describes the states for each lifecycle.
About Lifecycles Viewing an Object's Lifecycle Tasks/Signatures Tab of the Lifecycle PowerView Page Working with Lifecycle Approvals Approvals Tab on the Lifecycle PowerView Approving or Rejecting a Task Reassigning a Task Adding an Approval Task Adding Approvers from a Route Template to a Task Approving Multiple Tasks Approve Assigned Tasks Page Promoting and Demoting an Object Promoting and Demoting Groups of Objects Select Rules for Validation Report Promote Trigger Validation Report Running a Promote Trigger Validation Report Applying a Signature